Engines that are originally designed for a selected thrust can be operated at substantially higher or lower thrust levels successfully but such change frequently requires revision in engine opertion that must be compensated for. For example a higher turbine inlet pressure will require changes in the cooling air pressure requirements for the turbine rotor. Changes in the cooling air pressure may change the thrust load on the thrust bearing for the rotor or in a split engine the thrust load on a high pressure turbine rotor. The permissible load on the thrust bearing may be exceeded by a relatively small increase in the rotor cooling air pressure since this change in the air pressure may impact the entire front surface of the turbine disk and thus change the bearing load significantly. If the thrust bearing loading could be made independent of the thrust loads on the engine, any engine could be more readily adapted for substantially higher thrust levels without the need for significant revisions of the engine.